Conventionally, a brake control device is known in which a depression force fluid pressure circuit which transmitting fluid pressure of fluid pressurized by the depression force of the brake pedal to a wheel cylinder and a fluid pressure control circuit regulating fluid pressure of fluid pressurized by a power fluid pressure generator by a linear control valve and transmitting to the wheel cylinder are arranged in parallel. The brake control device usually selects a normal control mode using the fluid pressure control circuit in time and switches a braking mode to a depression force fluid pressure mode using the depression force fluid pressure circuit when some kind of abnormality is detected.
In the normal control mode, a target fluid pressure is calculated based on a demand braking force which is generated in the brake control device, and degree of opening of the linear control valve is usually controlled so that the target fluid pressure is transmitted to the wheel cylinder. Generally the brake control system without using the depression force of such a brake pedal is called brake by wire method.
In the normal control mode, a master cut valve provided in the master flow path communicating with a master cylinder and a wheel cylinder is closed, and a simulator cut valve provided in the simulator flow path communicating the master cylinder and a stroke simulator is opened. Thereby, fluid becomes able to flow out from the master cylinder to the stroke simulator by the operation of the brake pedal, and the stroke operation of the brake pedal is enabled, and the operation reaction force increasing so that quantity of stepping forward of the brake pedal becomes big is obtained.
Patent Literature 1 discloses the technique to keep on having closed a simulator cut valve after a switch of the braking mode when the braking mode before the switch is a mode closing the simulator cut valve when the braking mode is switched during the brake operation by a driver. Because the simulator cut valve is set in a closed state in a depression force fluid pressure mode, when it is usually switched from the depression force fluid pressure mode to the normal control mode, the closed state of the simulator cutoff valve is maintained. Thereby, at the time of mode switching, it is prevented what the brake pedal gets into more than the expectation of the driver.